There are currently about 38,000 long-term Japanese residents in South Korea, as well as another 19,000 or so tourists and other short-term travelers. “If the U.S. decided on a military strike against the North, the Japanese government would start moving toward an evacuation on its own accord regardless of whether the American plans are public,” a Japanese government source said.
Tokyo is working on a four-tier emergency plan based on the severity of the situation: discouraging unessential travel to South Korea, discouraging all travel to South Korea, urging Japanese citizens there to evacuate, and finally, urging them to shelter in place.
Should skirmishes erupt between the two Koreas, for example, the Japanese government would discourage all new travel to South Korea. At the same time, it would urge citizens already there to evacuate using commercial flights. Although the Japanese Embassy would help secure airline reservations, the government’s role under this scenario would mainly be to provide information.
There’s a lot of commercial air traffic in the region, which would presumably all be grounded in the event of a military crisis. It’s also easy to imagine a mass exodus from Seoul, which is home to nearly half of the South’s 52 million people.
Foreign nationals in Korea had better have a plan in place, a backup plan, and a backup to the backup plan.